Spinal stenosis is a frequently encoimtered spinal condition in the elderlyS and commonly leads to mobility impairment and disability in older adults. The biomechanical abnormalities leading to symptoms in patients with spinal stenosis are poorly imderstood. Static canal diameter is a poor predictor of symptoms^ and does not consistently correlate with response to surgical decompression.3-6. Current treatment options include physical therapy, medications, injections, and surgery. Lumbar spine surgery is among the most common major procedures for patients over the age of 65. The use of such inaccurate static imaging to diagnose and guide treatment likely leads to unnecessary procedures with associated morbidity and mortality. In contrast to static imaging, a more accurate that forward flexion might induce advantageous spinal anatomic changes that facilitate symptom improvement. Evidence to support this conjecture is that patients with spinal stenosis are able to walk longer before onset of symptoms on an inclined treadmill, which facilitates forward flexion, compared to a flat treadmill.^ The key gap in knowledge to be addressed in this pilot study is a better imderstanding of the dynamic spinal mechanism underlying the clinical observation of delayed onset of symptoms with forward flexed walking. Insights into in vivo spinal dynamics can help inform future interventions, both rehabilitative and surgical. The data collected in this pilot, in combination with data from the parent study, will be used as preliminary data in a proposal for a clinical trial to examine the effectiveness of a flexion based exercise program in patients with spinal stenosis and to examine kinematic mechanisms of this improvement. These findings can also be used to plan an observational study of the ability of diameter change with inclined walking to predict surgical response. This pilot project therefore represents the initial work to support future studies which will have strong potential for clinical translation.